Stearic acid and Magnesium Stearate: Is it Safe?

It seems that every few weeks the question comes across my desk, ‘why do you put magnesium stearate in (product X)?’

Customers have invariably visited one of the nutraceutical website equivalents of tabloid journalism, seen an article about how magnesium stearate is harmful in some capacity (I’d point examples of these articles out, but I’d rather not support their behavior by helping them get page hits), and then call us and demand to know why we’re ‘poisoning’ them. Hopefully I can clear this up a little.

What are these compounds that have caused people to hate them so? Stearic acid belongs to a class of molecules called fatty acids. Fatty acids are basically just what they sound like, a molecule that is part fat-like and part acid. While fatty acids have several purposes, the greatest and most essential is in the makeup of the membranes that surround all our cells in our bodies. They become combined with other molecules to form the barrier that separates our cells from each other and their surroundings. Depending on what study you look at, stearic acid itself makes up around 30% of the fatty acids in our cell membranes.

So stearic acid makes up about 30% of a group of molecules that are an absolute required for ANY known living organism. I don’t think that meets most people’s definition of ‘toxic’. So where did that concept come from?

As far as I can tell, it came from research like this one:

“Molecular basis for the immunosuppressive action of stearic acid on T cells.” (Tebbey and Buttke, 1990)

But I’m sure to most people, the title looks like “…immunosupressive action of stearic acid…”. This study, and others like it, is how about when you take pure T cells (type of white blood cell), grow them in a petri dish, and feed them straight stearic acid as their only fatty acid source, the cells are unhappy and don’t function well as immune cells. This gives people the impression that stearic acid inhibits immune function. I’m sure that the researchers would cringe that their data is being co-opted for such an argument.

What’s the reason behind this effect? The immune cells were only given one thing to eat! Imagine if all you were given was one type of food! It doesn’t matter how healthy it is, you’re going to get sick from eating just spinach, just broccoli or only one type of any kind of food. Balance is always required.

If you’re still on the fence, think about it like this: the average intake for stearic acid is between 5 and 8 grams (for omnivores; vegetarians eat a little less). Given the average amount of magnesium stearate or stearic acid in a typical tablet, you’d need to take more than 20 tablets per day to equal 1% of the amount you already have in your diet. And you know what happens if you don’t eat enough stearic acid?

Dr. George Templeton is AOR’s Head of Product Development. Dr. Templeton holds a BSc in Biochemistry and a PhD in Biochemistry with a focus in Signal Transduction, from the University of Calgary. He has presented his doctoral research at several international conferences and published numerous peer-reviewed scientific studies. Dr. Templeton has a passion for elegant science and the effective use natural health solutions.